Get the fuel pump (the external fuel pump and bracket with filter) all fuel lines if possible, wiring and all engine related electronics ( boost control, MAF, coil, voltage regulator unless your going to a 3g alt. TFI and of course the wiring. Thrown in a new oil pump with pick up and pan from your 2.3 motor add a new water pump and thermostat . The best thing is to get the whole car. Get a 8 inch rear end from a Pinto V-6, the Mustang II will work but it's not a direct drop in. The stock 6 3/4 rear end might live for a while.